IntersectionObserver()

The IntersectionObserver() constructor creates and returns a new IntersectionObserver object.

Inputs: callback A function which is called when the percentage of the target element that is visible crosses a threshold. The callback receives as input two parameters: entries An array of IntersectionObserverEntry objects, each representing one threshold which was crossed, either becoming more or less visible than the percentage specified by that threshold. You should not assume the number of entries, because multiple threshold-crossing events may be reported in a single callback invocation. The entries are dispatched using a queue, so they should be ordered by the time they were generated, but you should preferably use IntersectionObserverEntry.time to correctly order them. observer The IntersectionObserver for which the callback is being invoked.